Newton D W, Kluza R B
Am J Hosp Pharm. 1980 Dec;37(12):1647-51.
The application of basic scientific principles to the practical problem of phenytoin precipitation in large volume parenteral solutions is reviewed. The solubility of phenytoin in i.v. admixtures depends on phenytoin's pKa and the i.v. solution pH as well as the admixture volume and the solubility of undissociated phenytoin in that admixture. Equations are derived that predict the solubility of phenytoin in i.v. admixtures, and illustrative examples are presented using the formulas. The effect of storage time on phenytoin solubility is discussed, and the effects of hydroalcoholic solvents (present in commercially available sodium phenytoin injection) and their dilution in aqueous admixtures are considered. Although simple equations can be used to predict the solubility of phenytoin sodium injection in i.v. fluids, the time required for a precipitate to develop cannot be predicted because of the variability in published studies.
本文综述了基础科学原理在大容量静脉输液中苯妥英沉淀这一实际问题上的应用。苯妥英在静脉输液混合液中的溶解度取决于苯妥英的pKa、静脉输液溶液的pH值、混合液体积以及未解离苯妥英在该混合液中的溶解度。推导了预测苯妥英在静脉输液混合液中溶解度的方程式，并给出了使用这些公式的示例。讨论了储存时间对苯妥英溶解度的影响，并考虑了含醇溶剂（市售苯妥英钠注射液中存在）及其在水性混合液中的稀释效果。虽然可以使用简单的方程式来预测苯妥英钠注射液在静脉输液中的溶解度，但由于已发表研究的变异性，无法预测沉淀形成所需的时间。
